TWI761449B - Composition for Optical Materials - Google Patents

Abstract

(式中，m表示0~4之整數，n表示0~2之整數)。Provides compositions for optical materials that can design optical materials with a wide range of physical properties. The composition for an optical material of the present invention contains a compound (A) represented by the following formula (1), 1,2,3,5,6-pentathhiepane (b), and if necessary, the following formula The content of the compound (B) represented by (2) is 0 to 30 mass % with respect to the total amount of the composition.

(In the formula, m represents an integer from 0 to 4, and n represents an integer from 0 to 2).

Description

Composition for Optical Materials

The present invention relates to optical components such as plastic lenses, lenses, optical fibers, information recording bases, filters, adhesives, etc., especially compositions for optical materials used in optical lenses such as plastic lenses for spectacles.

The main properties of optical materials, especially plastic materials required for spectacle lenses, are heat resistance, low specific gravity, high transparency and low yellowness, as well as high refractive index and high Abbe number. Optical properties, in recent years, in order to To achieve a high refractive index and a high Abbe number, a polymerizable composition for an optical material containing a polyepisulfide compound has been proposed (Patent Documents 1 to 3). In addition, for the purpose of improving designability, durability and optical properties, optical lenses such as spectacle lenses are dyed, hard-coated and anti-reflection coated. In carrying out these steps, the optical material is exposed to high temperature, which may cause problems due to thermal deformation. Therefore, it is desired to improve the heat resistance of the optical material. Various comonomers are added to the optical material composition for the purpose of increasing the refractive index of the optical material or improving the color tone stability. However, due to the addition of comonomers, the crosslinking density of the optical material obtained after polymerization tends to decrease and the heat resistance tends to deteriorate. From the viewpoint of heat resistance, the addition amount of comonomers is limited, which can improve the performance of optical materials. The subject of the limited range of characteristics. It is expected that a composition for an optical material of an optical material having a wide range of physical properties can be designed by improving the heat resistance as a reference and increasing the addition tolerance of a comonomer. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 10-298287 [Patent Document 2] Japanese Patent Laid-Open No. 2001-002933 [Patent Document 3] Japanese Patent Laid-Open No. 2010-242093

[The problem to be solved by the invention]

It is desired to provide a composition system for an optical material which can design an optical material with improved heat resistance and a wide range of physical properties. [means to solve the problem]

The inventors of the present invention found that an optical material having a wide range of physical properties can be designed by a specific composition containing the compound represented by the following formula (1). That is, the present invention is as follows.

(式中，m表示0~4之整數，n表示0~2之整數)。 　　[2] 如[1]之光學材料用組成物，其中化合物(A)之含量，相對於組成物總量而言，為20~80質量%。 　　[3] 如[1]或[2]之組成物，其進一步含有聚硫醇(a)。 　　[4] 如[3]之組成物，其中聚硫醇(a)，為由1,2,6,7-四巰基-4-硫雜庚烷、甲烷二硫醇、(氫硫基甲基二氫硫基)甲烷硫醇、雙(2-巰基乙基)硫醚、2,5-雙(巰基甲基)-1,4-二硫雜環己烷、1,2-雙(2-巰基乙硫基)-3-巰基丙烷、4,8-二巰基甲基-1,11-二巰基-3,6,9-三硫雜十一烷、4,7-二巰基甲基-1,11-二巰基-3,6,9-三硫雜十一烷、5,7-二巰基甲基-1,11-二巰基-3,6,9-三硫雜十一烷、1,1,3,3-肆(巰基甲硫基)丙烷、四巰基季戊四醇、1,3-雙(巰基甲基)苯、1,4-雙(巰基甲基)苯及環硫乙烷甲烷硫醇中選擇之至少1種。 　　[5] 如[1]~[4]中任一項之組成物，其進一步含有硫。 　　[6] 如[1]~[5]之組成物，其中化合物(A)與化合物(B)之質量比為45：55~100：0。 　　[7] 如[1]~[6]之組成物，其中化合物(A)與1,2,3,5,6-五硫雜環庚烷(b)之質量比為25：75~95：5。 　　[8] 如[1]~[7]中任一項之組成物，其中1,2,3,5,6-五硫雜環庚烷(b)之含量，相對於組成物總量而言，為5~70質量%。 　　[9] 如[1]~[8]中任一項之組成物，其中相對於組成物總量而言，含有 　　化合物(A) 20~80質量%； 　　1,2,3,5,6-五硫雜環庚烷(b) 5~70質量%； 　　化合物(B) 0~30質量%； 　　聚硫醇(a) 0~10質量%；及 　　硫 0~25質量%。 　　[9a] 如[1]~[9]中任一項之組成物，其中相對於組成物總量而言，含有 　　化合物(A) 20~80質量%； 　　1,2,3,5,6-五硫雜環庚烷(b) 5~70質量%； 　　化合物(B) 0~30質量%； 　　聚硫醇(a) 0~10質量%； 　　硫 0~25質量%； 　　聚合觸媒 0~10質量%；及 　　聚合調整劑 0~5質量%。 　　[10] 如[1]~[9]、[9a]中任一項之組成物，其中使前述組成物硬化後，於25℃之e線的折射率為1.75以上。 　　[11] 一種光學材料，其係使如[1]~[10]、[9a]中任一項之組成物硬化而得。 　　[12] 一種光學透鏡，其含有如[11]之光學材料。 [發明之效果][1] A composition for an optical material, comprising a compound (A) represented by the following formula (1), 1,2,3,5,6-pentathiepane (b), and as required The compound (B) represented by the formula (2), the content of the compound (B) is 0 to 30% by mass relative to the total amount of the composition;

(In the formula, m represents an integer from 0 to 4, and n represents an integer from 0 to 2). [2] The composition for an optical material according to [1], wherein the content of the compound (A) is 20 to 80% by mass relative to the total amount of the composition. [3] The composition according to [1] or [2], which further contains a polythiol (a). [4] The composition of [3], wherein the polythiol (a) is composed of 1,2,6,7-tetramercapto-4-thiaheptane, methanedithiol, (hydrothiomethyl) Dihydrothio)methanethiol, bis(2-mercaptoethyl)sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiacyclohexane, 1,2-bis(2- mercaptoethylthio)-3-mercaptopropane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1 ,11-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 1, 1,3,3-tetra(mercaptomethylthio)propane, tetramercaptopentaerythritol, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, and thioethanemethane mercaptan Choose at least 1 of them. [5] The composition according to any one of [1] to [4], which further contains sulfur. [6] The composition of [1]~[5], wherein the mass ratio of compound (A) to compound (B) is 45:55~100:0. [7] The composition of [1]~[6], wherein the mass ratio of compound (A) to 1,2,3,5,6-pentathiepane (b) is 25:75~95: 5. [8] The composition according to any one of [1] to [7], wherein the content of 1,2,3,5,6-pentathiepane (b) is relative to the total amount of the composition , is 5 to 70 mass %. [9] The composition according to any one of [1] to [8], which contains 20 to 80 mass % of compound (A) relative to the total amount of the composition; 1,2,3,5,6- Pentathiepane (b) 5-70 mass %; compound (B) 0-30 mass %; polythiol (a) 0-10 mass %; and sulfur 0-25 mass %. [9a] The composition according to any one of [1] to [9], which contains 20 to 80% by mass of compound (A) with respect to the total amount of the composition; 1,2,3,5,6- Pentathiepane (b) 5-70 mass %; Compound (B) 0-30 mass %; Polythiol (a) 0-10 mass %; Sulfur 0-25 mass %; Polymerization catalyst 0-10 mass %; and polymerization regulator 0~5 mass %. [10] The composition according to any one of [1] to [9] and [9a], wherein the refractive index at e-line at 25° C. after curing the composition is 1.75 or more. [11] An optical material obtained by curing the composition according to any one of [1] to [10] and [9a]. [12] An optical lens containing the optical material as [11]. [Effect of invention]

The composition for optical materials of the present invention has one or more of the following effects. (1) By using the optical material composition of the present invention, it is possible to design an optical material with improved heat resistance, increased tolerance for addition of comonomers, and a wide range of physical properties. (2) Optical materials with excellent heat resistance and high refractive index can be obtained.

Hereinafter, the present invention will be described in detail by describing embodiments, examples, and the like, but the present invention is not limited to the embodiments, examples, and the like shown below, and can be implemented with arbitrary modifications without departing from the gist of the present invention.

(式中，m表示0~4之整數，n表示0~2之整數)。 　　以下詳細說明各構成要素。One aspect of the present invention relates to a composition for an optical material comprising a compound (A) represented by the following formula (1), 1,2,3,5,6-pentathiepane (b), and The compound (B) represented by the following formula (2) as needed, the content of the compound (B) is 0 to 30% by mass relative to the total amount of the composition;

(In the formula, m represents an integer from 0 to 4, and n represents an integer from 0 to 2). Each constituent element will be described in detail below.

該化合物之獲得方法並無特殊限定，例如能夠以四巰基季戊四醇為原料以日本特開平09-110979記載之方法合成，可適合地使用。[Compound (A)] The compound (A) is a sulfide compound having four thioepoxy groups represented by the following formula (1), and has the effect of improving the refractive index and heat resistance of an optical material.

The method for obtaining this compound is not particularly limited, and for example, it can be synthesized by the method described in Japanese Patent Laid-Open No. 09-110979 using tetramercaptopentaerythritol as a raw material, and it can be suitably used.

The ratio of the compound (A) in the composition for optical materials is 0.1 to 99.5 mass %, preferably 3 to 90 mass %, more preferably 5 to 90 mass %, and more It is preferably 10 to 90 mass %, still more preferably 20 to 90 mass %, particularly preferably 20 to 80 mass %, and most preferably 20 to 50 mass %. Within this range, a sufficient heat resistance improvement effect can be obtained.

[Polythiol (a)] The composition for optical materials may contain polythiol (a) as needed. The polythiol (a) is a thiol compound having two or more mercapto groups per molecule. The polythiol (a) has the effect of improving the color tone of the resin obtained from the composition for optical materials of the present invention when heated. The polythiol used in the present invention is not particularly limited, but in terms of its high color tone improvement effect, preferable specific examples include 1,2,6,7-tetramercapto-4-thiaheptane, methanedi Thiol, (mercaptomethylthio)methanethiol, bis(2-mercaptoethyl)sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiacyclohexane , 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4 ,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9- Trithiaundecane, 1,1,3,3-tetra(mercaptomethylthio)propane, tetramercaptopentaerythritol, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl) Benzene, and thioethanemethane mercaptan, preferably bis(2-mercaptoethyl) sulfide, 1,2,6,7-tetramercapto-4-thiaheptane, most preferably 1,2, 6,7-Tetramercapto-4-thiaheptane. A commercially available product or one synthesized by a known method can be used for these, and two or more kinds can be used in combination. A commercially available product or one synthesized by a known method can be used for these, and two or more kinds can be used in combination.

The ratio of the polythiol (a) in the composition for optical materials is preferably 0 to 25 mass % (for example, 0.1 to 25 mass %), more preferably 0 to 20 mass % ( For example, 0.5-20 mass %), 0-10 mass % (for example, 0.5-10 mass %) is more preferable, and 0-5 mass % (for example, 0.5-5 mass %) is especially preferable. With this range, the balance between the color tone stabilization effect and the heat resistance becomes better.

1,2,3,5,6-五硫雜環庚烷(b)之獲得方法並無特殊限制。可使用市售品，亦可由原油或動植物等之天然物中採取萃取，又亦可由公知方法合成。 　　合成法之一例，可列舉N. Takeda等，Bull. Chem. Soc. Jpn., 68, 2757(1995)、F. Feher等，Angew. Chem. Int. Ed., 7, 301(1968)、G. W. Kutney等，Can. J. Chem, 58, 1233(1980)等記載之方法。[1,2,3,5,6-Pentathiepane (b)] 1,2,3,5,6-Pentathiepane (b) is represented by the following formula (b) A compound which has the effect of raising the refractive index of the optical material (resin) obtained from the composition for optical materials of this invention.

The method for obtaining 1,2,3,5,6-pentathiepane (b) is not particularly limited. Commercially available products can be used, or they can be extracted from natural products such as crude oil, animals and plants, or they can be synthesized by known methods. An example of the synthesis method includes N. Takeda et al., Bull. Chem. Soc. Jpn., 68, 2757 (1995), F. Feher et al., Angew. Chem. Int. Ed., 7, 301 (1968), GW The method described by Kutney et al., Can. J. Chem, 58, 1233 (1980) et al.

The ratio when 1,2,3,5,6-pentathiepane (b) is used in the composition for optical materials is preferably 5 to 70% by mass, more preferably 5 to 70% by mass relative to the total amount of the composition It is 5-50 mass %. Within this range, the improvement of the refractive index and the transparency of the optical material can be achieved.

The mass ratio of compound (A) to 1,2,3,5,6-pentathiepane (b) (compound (A): 1,2,3,5,6-pentathiepane ( b)), preferably 25:75~95:5. By being within this range, a high refractive index and an excellent color tone can be achieved at the same time.

(式中，m表示0~4之整數，n表示0~2之整數)。[Compound (B)] The composition for optical materials may contain the compound (B) as needed. The compound (B) is an episulfide compound having two episulfide groups represented by the following formula (2). The compound (B) can be copolymerized with the compound (A), and by using it together with the compound (A), it has the effect of improving the hardening reactivity.

(In the formula, m represents an integer from 0 to 4, and n represents an integer from 0 to 2).

Among them, bis(β-epithiopropyl) sulfide and bis(β-epithiopropyl) disulfide are particularly preferred, and bis(β-epithiopropyl) sulfide is particularly preferred. Bis(β-epithiopropyl) sulfide corresponds to the compound with m=n=0 in the above formula (2), and bis(β-epithiopropyl) disulfide corresponds to m=0 in the above formula (2) and n=1 compound.

The content of the compound (B) in the composition for optical materials is preferably 0 to 30% by mass, more preferably 0 to 25% by mass, with respect to the total amount of the composition. Within this range, the hardening reactivity can be improved while ensuring an excellent color tone.

The mass ratio of compound (A) to compound (B) (compound (A):compound (B)) is preferably 45:55 to 100:0, more preferably 50:50 to 100:0. By being within this range, a high refractive index and an excellent color tone can be achieved at the same time.

[Sulfur] The composition for optical materials may contain sulfur as required. A sulfur system has the effect of raising the refractive index of the optical material (resin) obtained from the composition for optical materials of this invention. The shape of the sulfur used in the present invention can be any shape. Specifically, the sulfur includes fine powder sulfur, colloidal sulfur, precipitated sulfur, crystalline sulfur, sublimed sulfur, and the like, and from the viewpoint of the dissolution rate, fine powder sulfur with fine particles is preferred. The particle size (diameter) of the sulfur used in the present invention is preferably less than 10 meshes. When the particle size of sulfur is larger than 10 mesh, the sulfur is not easy to dissolve completely. The particle size of sulfur is more preferably smaller than 30 mesh, and most preferably smaller than 60 mesh. The purity of the sulfur used in the present invention is preferably more than 98%, more preferably more than 99.0%, more preferably more than 99.5%, and most preferably more than 99.9%. When the purity of sulfur is more than 98%, the color tone of the obtained optical material is more improved than when it is less than 98%. Sulfur satisfying the above conditions can be easily obtained as a commercial product and can be used appropriately.

In the composition for optical materials, the ratio of sulfur is 0 to 40 mass % (for example, 1 to 40 mass %), preferably 0 to 30 mass % (for example, 5 to 30 mass %, with respect to the total amount of the composition). , 10 to 30 mass %), more preferably 0 to 25 mass % (for example, 5 to 25 mass %), and particularly preferably 0 to 20 mass % (for example, 5 to 20 mass %). This is because within this range, the balance between the refractive index improvement effect and the solubility is excellent.

An example of the composition of a preferable composition for optical materials is shown below. With respect to the total amount of the composition, the compound (A) contains 20 to 80 mass % (more preferably 20 to 50 mass %); 1,2,3,5,6-pentathiepane (b) 5 ~ 70 mass % (more preferably 5 ~ 50 mass %); Compound (B) 0 ~ 30 mass % (more preferably 0 ~ 25 mass %); Polythiol (a) 0 ~ 10 mass % (more preferably 0-5 mass %); and sulfur 0-25 mass % (more preferably 0-20 mass %) composition for optical materials. Another example of the composition of a preferable optical material composition is shown below. With respect to the total amount of the composition, the compound (A) contains 20 to 80 mass % (more preferably 20 to 50 mass %); 1,2,3,5,6-pentathiepane (b) 5 ~ 70 mass % (more preferably 5 ~ 50 mass %); Compound (B) 0 ~ 30 mass % (more preferably 0 ~ 25 mass %); Polythiol (a) 0 ~ 10 mass % (more preferably 0-5 mass %); Sulfur 0-25 mass % (more preferably 0-20 mass %); Polymerization catalyst 0-10 mass % (more preferably 0.0001-10 mass %); And polymerization regulator 0-5 mass % (preferably 0.0001 to 5.0 mass %) of the composition for optical materials.

[Other Components] Furthermore, the composition for optical materials of the present invention may contain other polymerizable compounds that can be copolymerized with the compound (A). As other polymerizable compounds, episulfide compounds other than compound (A) and compound (B), vinyl compounds, methacrylic compounds, acrylic compounds and allyl compounds can be exemplified. The addition amount of other polymerizable compounds is not particularly limited as long as it is within a range that does not inhibit the effects of the present invention, and for example, it is 0 to 30% by mass relative to the total amount of the composition.

In addition, it is also possible to add a part of the components of the present invention (including polymers obtained by prepolymerizing the components) for the purpose of improving various properties such as oxidation resistance, weather resistance, dyeability, strength, and refractive index. Or all the reacted compounds can be used as various performance modifiers for polymerization and hardening. Specific examples of compounds that can react with a part or all of such components include epoxy compounds, iso(thio)cyanates, carboxylic acids, carboxylic acid anhydrides, phenols, amines, and vinyl compounds. , Allyl compounds, acrylic compounds and methacrylic compounds. The addition amount of these compounds is not particularly limited as long as it is a range that does not inhibit the effects of the present invention, and for example, it is 0 to 10% by mass with respect to the total amount of the composition.

Moreover, in order to polymerize and harden, the composition for optical materials may contain a polymerization catalyst and/or a polymerization regulator. A composition for an optical material in one form further contains a polymerization catalyst. Examples of the polymerization catalysts include amines, phosphines, quaternary ammonium salts, quaternary phosphonium salts, tertiary periconium salts, secondary iodonium salts, inorganic acids, Lewis acids, organic acids, silicic acids, tetramines. Fluorinated boric acids, peroxides, azo compounds, condensates of aldehydes and ammonia compounds, guanidines, thioureas, thiazoles, sulfinamides, thiurams, dithioamines Formates, xanthates, acid phosphates, etc. Preferred are amines, phosphines, quaternary ammonium salts, and quaternary phosphonium salts. The polymerization catalyst may be used alone or in combination of two or more. The addition amount of the polymerization catalyst is not particularly limited, for example, it is 0.0001~10% by mass relative to the total amount of the composition. The composition for optical materials of one form further contains a polymerization regulator. As the polymerization regulator, halides of Groups 13 to 16 of the long periodic table can be exemplified. Preferred among these are halides of silicon, germanium, tin, and antimony, and more preferred are chlorides of germanium, tin, and antimony having alkyl groups. The polymerization modifier may be used alone or in combination of two or more. The addition amount of the polymerization modifier is not particularly limited, for example, it is 0.0001~5.0% by mass relative to the total amount of the composition.

Moreover, additives, such as a well-known antioxidant, a bluing agent, an ultraviolet absorber, a deodorizer, an adhesion improver, and a mold release improver, may be added. The amount of these additives is not particularly limited as long as it is a range that does not inhibit the effects of the present invention, and for example, it is 0 to 10% by mass relative to the total amount of the composition.

[Composition for optical materials] The composition for optical materials of the present invention is prepared by combining compound (A), 1,2,3,5,6-pentathiepane (b), and a compound as needed (B), polythiol (a), sulfur, and other components are mixed in a uniform state and prepared.

[Curing of the composition for optical materials] The composition for optical materials can be made into optical materials by injection-molding the composition for optical materials in a mold such as a mold and polymerizing. In order to achieve high transparency of the optical material, it is preferable to perform degassing treatment in advance before injecting the polymerizable composition for the optical material into the mold. From the viewpoint of improving the quality of the optical material of the present invention, it is preferable to filter and remove impurities with a filter having a pore size of about 0.1 to 5 μm during injection molding of the optical material composition of the present invention.

The polymerization (hardening) of the composition for optical materials of the present invention is usually carried out under the following conditions. The hardening time is usually 1~100 hours, and the hardening temperature is usually -10℃~140℃. The polymerization (hardening) is performed by a step of maintaining a specific polymerization temperature for a specific time, a step of performing a temperature increase of 0.1°C to 100°C/h, a step of performing a temperature drop of 0.1°C to 100°C/h, or a combination of these steps. Furthermore, the curing time refers to the polymerization curing time including the heating process/cooling process, etc., and includes the step of heating/cooling toward the specific polymerization (hardening) temperature in addition to the step of maintaining at the specific polymerization (hardening) temperature. In addition, in order to remove the deformation of the optical material of the present invention, it is preferable to anneal the obtained optical material at a temperature of 50 to 150° C. for about 10 minutes to 5 hours after curing. The resulting optical material can also be further subjected to surface treatments such as dyeing, hard coating, impact-resistant coating, anti-reflection, and anti-fogging properties as required.

As described above, an optical material can be produced by polymerizing and curing the above-mentioned composition for an optical material. The present invention also includes a method for producing an optical material comprising polymerizing and curing the above-mentioned composition for an optical material. Further, an optical material (molded body; cured product; cured resin) obtained by curing the above-mentioned composition for an optical material is also included in the present invention.

The composition for optical materials of the present invention can achieve excellent heat resistance by containing the compound (A) and 1,2,3,5,6-pentathiepane (b), and can reduce the cost of other comonomers. Influence of heat resistance reduction due to addition. Therefore, various comonomers can be blended in the composition for optical materials, and the blending amount thereof can be increased, whereby an optical material having a wide range of physical properties can be designed. In particular, the composition for an optical material according to an embodiment of the present invention can provide an optical material with excellent heat resistance and high refractive index.

The refractive index of the optical material when the composition for optical materials is cured is preferably 1.70 or more, more preferably 1.75 or more, and particularly preferably 1.78 or more. The refractive index can be measured by a refractometer, which is a value measured by e-line (wavelength: 546.1 nm) at 25°C. Regarding the heat resistance of the optical material, there is no softening point when the temperature of the optical material is raised, or the softening point is preferably 50°C or higher, more preferably 55°C or higher. The softening point can be determined by TMA (Thermal Mechanical Analysis). The smaller the peak value of DTMA in the temperature differential curve of the TMA curve, the less likely to cause softening due to heat. Therefore, the peak value of DTMA is preferably 2 μm/°C or less.

The optical material of the present invention can be used in various applications such as optical members, machine parts materials, electrical/electronic parts materials, automobile parts materials, civil engineering materials, molding materials, etc., and also materials for coatings or adhesives. Among them, especially optical materials, such as glasses lenses, photographic lenses for (digital) cameras, light beam condensing lenses, lenses for light diffusion, etc.; LED sealing materials, optical adhesives, bonding materials for light transmission, optical fibers, prisms Optical applications such as transparent glass or cover glass for mirrors, filters, diffraction gratings, watch glass, cover glass for display devices, etc.; substrates for display elements such as LCD, organic EL or PDP; substrates for color filters It is suitable for display device applications such as coating agents (coating films) for touch panel substrates, information recording substrates, display backlights, light guide plates, display protective films, anti-reflection films, anti-fog films, etc. As the above-mentioned optical materials, optical materials such as optical lenses, crystals, optical fibers, information recording bases, optical filters, etc. are particularly suitable, and among them, optical lenses are particularly suitable. The optical lens manufactured using the composition for optical materials of the present invention is excellent in stability, hue, transparency, etc., so it can be used in fields such as telescopes, binoculars, television projectors, etc., where high-priced high-refractive-index glass lenses have been used in the past. , is extremely useful. Preferably, it is used in the form of an aspherical lens as required. [Example]

Hereinafter, the present invention will be specifically described by way of examples, but the embodiments can be appropriately changed as long as the effects of the present invention are exhibited.

Analysis and evaluation of optical materials were performed by the following methods. [Refractive index of optical material] The refractive index of the optical material was measured at e-line at 25°C using a digital precision refractometer (KPR-2000, manufactured by Shimadzu Corporation). [Evaluation of heat resistance of optical materials] The sample was cut out to a thickness of 3 mm, a load of 50 g was applied to a pin of 0.5 mmφ, and the temperature was raised at 10°C/min to perform TMA measurement (manufactured by SEIKO INSTRUMENTS, TMA/SS6100), and the obtained TMA curve was obtained. The DTMA peak temperature and peak value of the temperature differential curve are evaluated. The smaller the peak value, the less likely it is to cause softening due to heat, and it is estimated that the heat resistance is high. In particular, when the peak is negative, or there is no peak, it is regarded as no softening point.

[Synthesis Example 1] Synthesis of tetra(β-epithiopropylthiomethyl)methane (Compound A1) To 10.0 g (0.050 mol) of tetramercaptopentaerythritol, 50 mL of methanol was added, and the mixture was cooled to 5°C. After adding 0.42 g (0.0049 mol) of a 48% aqueous sodium hydroxide solution to this solution, 20.3 g (0.22 mol) of epichlorohydrin was dropped while maintaining the solution at 15°C or lower. After the dropping was completed, stirring was further performed at 5°C for 1 hour. After that, while cooling the solution to 5°C, a solution obtained by dissolving 16.3 g (0.20 mol) of a 48% aqueous sodium hydroxide solution in 20 mL of methanol was dropped. After completion of the dropping, stirring was further performed for 2 hours, and 100 mL of toluene and 100 mL of water were added. The toluene layer was washed three times with water, and the solvent was distilled off to obtain 20.1 g (0.047 mol) of tetra(β-glycidylthiomethyl)methane. 100 mL of toluene, 100 mL of methanol, 1.24 g (0.012 mol) of acetic anhydride, and 30.5 g (0.40 mol) of thiourea were added to the obtained 20.1 g (0.047 mol) of (β-glycidylthiomethyl)methane, and the mixture was heated at 20°C. Stirring was carried out for 24 hours. Then, 400 mL of toluene and 400 mL of 5% sulfuric acid were added, the toluene layer was washed three times with water, and the solvent was distilled off to obtain 16.8 g of a crude product of tetrakis (β-epithiopropylthiomethyl)methane. By further subjecting the crude product to silica gel column purification, 11.2 g (0.023 mol) of tetra(β-epithiopropylthiomethyl)methane (hereinafter referred to as compound A1) was obtained. The compound A1 used in the following experiments was synthesized by this method.

[Example 1] 65 parts by mass of compound (A) (β-epithiopropylthiomethyl)methane (compound A1), 1,2,3,5,6-pentathiepane (b ) (hereinafter simply referred to as "pentathiepane (b)") 35 parts by mass, and 0.02 parts by mass of tetra-n-butylphosphonium bromide as a polymerization catalyst and two-n- as a polymerization regulator 0.05 mass part of butyltin dichloride was mixed, and vacuum degassing was performed, and the composition for optical materials was obtained. The obtained composition for optical materials was heated at 30°C for 10 hours, heated to 100°C over 10 hours, and finally heated at 100°C for 5 hours to polymerize and harden. After standing to cool, annealing treatment was performed at 120° C. for 30 minutes. The evaluations of the obtained optical materials are summarized in Table 1.

[Examples 2 to 12, Comparative Examples 1 to 4] Following the compositions shown in Table 1, the same operations as in Example 1 were performed to obtain optical materials. The evaluations of the obtained optical materials are summarized in Table 1.

In addition, the numerical value in a table|surface represents content (mass part) of the compound in a composition. In addition, the symbols a1 to a3 and B1 and B2 described together with the numerical values in the table indicate the compounds used. The compounds in the table used the following. A1: tetra(β-epithiopropylthiomethyl)methane a1: bis(2-mercaptoethyl)sulfide a2: 1,3-bis(mercaptomethyl)benzene a3: 1,2,6,7- Tetramercapto-4-thiaheptane B1: bis(β-epithiopropyl) sulfide B2: bis(β-epithiopropyl) disulfide Furthermore, compound a3 can be described in Japanese Patent Laid-Open No. 2005-263791, for example. Synthesized by the method described in No.

From the above Table 1, it was confirmed that the compound (A) represented by the formula (1), 1,2,3,5,6-pentathiepane (b), and polythiol (a) as needed were used. In the case of the composition for optical materials containing sulfur (Examples 1 to 4), an optical material having a high refractive index and excellent heat resistance can be obtained. In addition, it was confirmed that when a specific amount of compound (B) was further contained (Examples 5 to 12), an optical material having a high refractive index and excellent heat resistance was also obtained. In particular, Examples 8~ in which specific amounts of compound (A), compound (B), 1,2,3,5,6-pentathiacycloheptane (b), polythiol (a) and sulfur were blended In 12, it was confirmed that a high refractive index exceeding 1.79 and excellent heat resistance could be achieved. On the other hand, in Comparative Examples 1 to 3 not containing the compound (A) or in Comparative Example 4 in which the content of the compound (B) exceeded 30 mass %, poor heat resistance was confirmed. [Industrial Availability]

The cured product obtained by polymerizing and curing the composition for an optical material of the present invention can be suitably used as an optical material such as a plastic lens, a lens, an optical fiber, an information recording base, an optical filter, and an adhesive.

Claims (11)

A composition for an optical material comprising a compound (A) represented by the following formula (1) and 1,2,3,5,6-pentathiepane (1,2,3,5,6-pentathiepane) ) (b), or a compound (A) represented by the following formula (1), 1,2,3,5,6-pentathiepane (b) and a compound represented by the following formula (2) ( B), the content of compound (A) is 20~80% by mass relative to the total amount of the composition, and the content of compound (B) is 0~10% by mass relative to the total amount of the composition;

(In the formula, m represents an integer from 0 to 4, and n represents an integer from 0 to 2). The composition of claim 1, which further contains a polythiol (a). The composition of claim 2, wherein the polythiol (a) is composed of 1,2,6,7-tetramercapto-4-thiaheptane, methanedithiol, (hydrothiomethyl dihydrogen sulfide) base) methanethiol, bis(2-mercaptoethyl) sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiacyclohexane, 1,2-bis(2-mercaptoethyl sulfide yl)-3-mercaptopropane, 4,8-dimercapto Dimercapto-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiadecane Monoalkane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 1,1,3,3-tetra(mercaptomethylthio)propane, tetrakis At least one selected from the group consisting of mercaptopentaerythritol, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, and thioethanemethanethiol. The composition according to any one of claims 1 to 3, which further contains sulfur. The composition according to any one of claims 1 to 3, wherein the mass ratio of compound (A) to compound (B) is 45:55 to 100:0. The composition according to any one of claims 1 to 3, wherein the mass ratio of compound (A) to 1,2,3,5,6-pentathiepane (b) is 25:75 to 95:5 . The composition according to any one of claims 1 to 3, wherein the content of 1,2,3,5,6-pentathiepane (b), relative to the total amount of the composition, is 5 to 70 quality%. The composition according to any one of claims 1 to 3, wherein with respect to the total amount of the composition, the compound (A) contains 20 to 80 mass %; 1,2,3,5,6-pentathiepane Alkane (b) 5-70 mass %; compound (B) 0-10 mass %; polythiol (a) 0-10 mass %; and sulfur 0-25 mass %. The composition according to any one of claims 1 to 3, wherein the refractive index at e-line at 25°C after curing the composition is 1.75 or more. An optical material obtained by hardening the composition according to any one of Claims 1 to 9. An optical lens comprising the optical material of claim 10.